BCLN BIOLOGY 12 – Rev July 2014
Unit 14 ~ Learning Guide
Name:________________
INSTRUCTIONS
Complete the following notes and questions as you work through the related lessons.
You are required to have this package completed BEFORE you write your unit test. Do
your best and ask questions about anything that you don't understand BEFORE you
write the unit test.
U14 NOTES: URINARY SYSTEM (web notes)
Roles of Organs in Excretion
Excretion
 The removal of ______________________ from the body (the useless and
____________________________________ of cellular reactions)
Skin



Excretes ___________________ (a solution of water,
salt, and some urea)
Used
to
____________________________
then
secretion of wastes.
Increase in wastes during times of renal failure (kidney)
Liver


____________________________________________
_.
Yellow pigment in _________ is also formed from the
breakdown of ___________ by the _________. It is
then deposited in the blood and later removed by the
____________.
Lungs

Expiration removes ______________________ but it
also results in the loss of water.
Page 1 of 17
BCLN BIOLOGY 12 – Rev July 2014
Intestine
 Certain salts, such as those of _____________________
_______________________ directly into the cavity of the
_____________________________________________
lining it and become part of __________________.
Kidneys
 Excrete urine, which contains _____________________
_______________________ products of metabolism.
Entrance and Exit of Water
Enters:
1. Drink Water
2. Absorbed from food eaten
Exits:
1.
2.
3.
4.
5.
6.
Exhalation
Perspiration
Tears (small amounts)
Urination
Expectorating (phlegm)
Defecation
Urinary System Functions
1.
2.
3.
4.
Kidney - ___________________________________________________
Ureters - ___________________________________________________
Bladder - ___________________________________________________
Urethra - ___________________________________________________
Parts of the Kidney
When
a
kidney
is
sliced
longitudinally (sagittal section), it
shows 3 regions.
1. Outer granulated region called
the _____________________.
2. Striated or lined layer called the
_____________________.
Page 2 of 17
BCLN BIOLOGY 12 – Rev July 2014
3. Inner cavity called the ________________________ where urine collects.
The kidney lies in the lower, dorsal port of the abdomen. They receive blood from the
_________________________ to be cleaned.
The wastes, to be excreted, called ______________ collects in the ________________
region of each kidney before being conducted by _________________ through the
ureters down to the ___________________________. When the urinary bladder
becomes full, stretch receptor trigger __________________, and the fluid is excreted
via the urethra.
The Nephron
Microscopically, the kidney is composed of over 1 billion nephrons (or renal tubules).
Various parts of the nephron align in the kidney such that:
The cortex (outer region) contains:
1. ______________________________________________________________
2. ______________________________________________________________
3. ______________________________________________________________
The medulla (inner region) contains:
1. ______________________________________________________________
Both the cortex and medulla contain portions of the _________________________
Page 3 of 17
BCLN BIOLOGY 12 – Rev July 2014
Renal Artery
 Bring blood to the _______________ to be "cleaned".
 High _____________ content.
Renal Veins
 Returns blood that is _______________.
 Low ____________ content, high glucose.
Each nephron has its own blood supply. Including 2 capillary regions:
1. At the _____________________________.
2. Surround the rest of the ________________________________.
Steps of Urine Formation
1. ________________________________________________________________
2. ________________________________________________________________
3. ________________________________________________________________
4. ________________________________________________________________
5. ________________________________________________________________
Function of the Nephron
1. Pressure Filtration
Blood enters the __________________________________________________
________________________________________________________________
____________________________ water, nutrients, and wastes out of the
glomerulus and into Bowman's Capsule. Large organic molecules do not exit the
blood (not filtered). _________________________________________________
________________________________________________________________.
Blood pressure is very important. If blood pressure is too _________, filtration
will not occur. A hormone called _____________ is released from a specialized
tissue in the ______________ that causes the constriction of the Glomerulus and
thus, the blood pressure is increased to an adequate level.
Filtered Blood Components
Non-Filtered Blood Components
Water
Formed Elements - Blood
Nutrients
Cells
Nitrogenous Wastes
Platelets
Salt (ions)
Proteins
Page 4 of 17
BCLN BIOLOGY 12 – Rev July 2014
2. Selective Reabsorption
Occurs mainly at the _____________
_____________________________.
Required nutrients (glucose, amino
acids,
vitamins,
minerals,
salt
molecules and some water) are
reabsorbed into the peritubular
capillary network. _______________
____________________.
3. Water Reabsorption
The body cannot afford to lose
all this water. It must be
reabsorbed into the blood.
_________________________
_________________________
_________________________
_________________________
_________________________
_________________________
and water follows the sodium
by osmosis (to even out electrical and concentration gradients).
Water is _____________________ along the entire length of the nephron.
Therefore urine is concentrated. The blood in the capillaries are
__________________ to the fluids in the fluid spaces.
The loop of Henle creates a high osmotic pressure in the medulla. The fluid going
up the distal side of the loop of Henle has a greater ______________________
of wastes and little nutrient value.
4. Tubular Excretion
Occurs at the distal convoluted tubule. Excess molecules in the
______________, such as H+ ions, Histamine, Penicillin, and ammonia are
secreted into the tubule from the blood, thereby helping to
___________________________________. Helps maintain blood _____.
5. Excretion
Concentrated urine from the _________________________ collect and goes to
the __________________________.
Page 5 of 17
BCLN BIOLOGY 12 – Rev July 2014
Summary of Nephron Function/Urine Production
YOU SHOULD GO THROUGH THE NEPHRON FUNCTION/ URINE FORMATION
TUTORIAL BEFORE PROCEEDING ANY FURTHER!
Antidiuretic Hormone (ADH)
Good example of negative
feedback loop.
ADH - _________________
_______________________
_________________.
ADH
increases
the
permeability of the distal
convoluted
tubule
and
collecting duct so that more
________________ can be
reabsorbed. Therefore a
decreased amount of urine
results, but an increase in
urine concentration. Water + Urea = Urine. ___________________________________
________________________. Urea is a waste product in the metabolism of proteins.
With more water being reabsorbed, blood volume tends to be increased.
If too little water is taken in orally the _______________________________ releases a
hormone into the nerve tract to the _________________________________ gland. The
posterior pituitary gland releases __________ and more water is absorbed by the
kidneys to maintain blood volume.
Page 6 of 17
BCLN BIOLOGY 12 – Rev July 2014
pH of blood is maintained by tubular excretion. If ____________________________,
hydrogen ions are secreted into the nephron.
Alcohol has a negative effect on ________. It sends a false message to the
hypothalamus that there is too much water in the blood. ADH is not released in fact it is
inhibited. Therefore _________________________________________. That is why, if
you drink alcohol, you urinate a lot and become dehydrated.
Aldosterone
Aldosterone is a hormones which regulate the level of _________________________
_________________________ in the blood. If sodium is too low, aldosterone causes
more sodium to be reabsorbed. If sodium concentration is too high the release of
aldosterone is inhibited.
Adrenal Cortex __________________________. The effect of this is the same as that
of ADH in that __________________________________________________________
_____________________________________________________________________.
Page 7 of 17
BCLN BIOLOGY 12 – Rev July 2014
U14 PRACTICE: URINARY SYSTEM
1. Define excretion. (2 marks)
2. Identify the substances excreted by the following structures. (5 marks)
a. sweat glands
b. lungs
c. liver
d. kidneys
e. large intestine
Page 8 of 17
BCLN BIOLOGY 12 – Rev July 2014
3. Label the following diagram of the urinary system and provide a brief description
of the function of the structure beside each label. Please be neat (8 marks)
4. Label the following diagram of a kidney and provide a brief description of the
function of the structure beside each label. You only need to label and describe
the structures indicated with letters. Please be neat. (8 marks)
A.
B.
C.
D.
Page 9 of 17
BCLN BIOLOGY 12 – Rev July 2014
5. Describe the various ways that water enters and exits the human body. (4 marks)
6. Compare and contrast the composition of blood plasma to the composition of
urine. (4 marks)
7. List the key substances that are selectively reabsorbed by the proximal
convoluted tubule. (6 marks)
8. List the key substances that are excreted by the distal convoluted tubule. (4
marks)
Page 10 of 17
BCLN BIOLOGY 12 – Rev July 2014
9. Label the following diagram of a nephron and provide a brief description of the
function of the structure beside each label. Please be neat. (16 marks)
Page 11 of 17
BCLN BIOLOGY 12 – Rev July 2014
10. Describe how the following events would change urine composition and
output/volume:
a. dehydration
b. prolonged exercise and sweating
c. drinking 3 liters of fluid
d. excessive salt consumption
e. excessive alcohol consumption
11. Explain how blood salt levels can influence blood volume and pressure. (3
marks)
Page 12 of 17
BCLN BIOLOGY 12 – Rev July 2014
12. Compare and contrast the role of ADH and aldosterone in regulating blood
pressure. (5 marks)
~ END OF BIOLOGY 12 UNIT 14 LEARNING GUIDE ~
Page 13 of 17
BCLN BIOLOGY 12 – Rev July 2014
UNIT 14 ANSWER KEY
14 PRACTICE: URINARY SYSTEM
1. Define excretion. (2 marks)
= removal of metabolic wastes (undesirable byproducts of cellular activities) from
the body
2. Identify the substances excreted by the following structures. (5 marks)
a. sweat glands = removal of water, salt and urea (a nitrogenous byproduct of preotein
metabolism)
b. lungs = removal of CO2 (a byproduct or cellular respiration)
c. liver = removal of old red blood cells including their pigments and nitrogenous byproducts
from protein metabolism (further processed out of blood by kidneys)
d. kidneys = production of urine which contains multiple waste products from cellular
metabolism
e. large intestine = excrete excess salts including of calcium and iron
3. Label the following diagram of the urinary system and provide a brief description of the function of
the structure beside each label. Please be neat (8 marks)
Page 14 of 17
BCLN BIOLOGY 12 – Rev July 2014
4. Label the following diagram of a kidney and provide a brief description of the function of the
structure beside each label. You only need to label and describe the structures indicated with
letters. Please be neat. (8 marks)
A.
C.
D.
E.
5. Describe the various ways that water enters and exits the human body. (4 marks)
-
Enter by drinking and food consumption
-
Exits by exhalation, perspiring, tears, expectorating (spitting), defecation and
urination
6. Compare and contrast the composition of blood plasma to the composition of urine. (4 marks)
-
Plasma should be ~ 90% water and contain a variety of proteins, salts, nutrients
(including glucose) and wastes (especially if it has not been recently processed
through the kidneys
-
Urine should be mostly water and contain some salts, pigments from old red blood
cells, nitrogenous wastes, other metabolic wastes yet it should lack proteins and
nutrients (such as glucose)
7. List the key substances that are selectively reabsorbed by the proximal convoluted tubule. (6
marks)
-
Nutrients such as amino acids, glucose, vitamins, mineral and salts as well as some
water
8. List the key substances that are excreted by the distal convoluted tubule. (4 marks)
- Excess hydrogen ions, histamine, antibiotics such as penicillin if they are being
taken, ammonia (a nitrogenous byproduct of protein metabolism)
Page 15 of 17
BCLN BIOLOGY 12 – Rev July 2014
9. Label the following diagram of a nephron and provide a brief description of the function of the
structure beside each label. Please be neat. (16 marks)
G.
Renal arteriole carrying unfiltered (dirty) blood into
nephron
F. Glomerulus = knot of capillaries where pressure filtration
occurs forcing water, nutrients and waste out of blood of
glomerulus and into Bowman's (glomerular) capsule
E. Bowman's capsule = collects filtrate from the glomerulus
H. Proximal Convoluted Tubule (PCT) = selective reabsorption
of nutrients such as glucose, salts, minerals and amino
acids back into blood from filtrate
B. Descending Arm of Loop of Henle = pump salt out of tubule
creating an osmotic gradient
C. Ascending Arm of Loop of Henle = water exits tubule following the osmotic gradient
created by the salt such that it can be reabsorbed into the blood
I.
Distal Convoluted Tubule (DCT) = tubular excretion where excess hydrogen ions,
histamine, ammonia and antibiotics such as penicillin are excreted from the blood into
the tubule
J. Peritubular Caplillary Network = where salt and water is reabsorbed from tubule/tissue
into blood
D. Renal venule carrying filtered blood
A. Collecting duct = collects concentrated urine from multiple nephrons
Page 16 of 17
BCLN BIOLOGY 12 – Rev July 2014
10. Describe how the following events would change urine composition and output/volume:
a. Dehydration = less urine, more concentrated
b. prolonged exercise and sweating = less urine, more concentrated
c. drinking 3 liters of fluid = more urine, less concentrated
d. excessive salt consumption = less urine, more concentrated as high blood salt leads to
water retention
e. excessive alcohol consumption = more urine, less concentrated as alcohol interferes
with the antidiuretic hormone (ADH) such that less water is reabsorbed from the
urine into the blood
11. Explain how blood salt levels can influence blood volume and pressure. (3 marks)
= high blood salt levels create blood that is hypertonic to urine such that more
water is reabsorbed into the blood, this increases blood volume which in turn
increases blood pressure.
12. Compare and contrast the role of ADH and aldosterone in regulating blood pressure. (5 marks)
= both ADH (antidiuretic hormone) and aldosterone are released in response to low
blood pressure and lead to feedback mechanisms that help to increase blood
pressure however they are released from different areas of the body in response to
different triggers
=ADH is released by the pituitary gland when the hypothalamus detects a high blood
salt concentration which is indicative of low blood pressure (recall concentration =
salt/water and if you decrease the volume of water you have a high salt
concentration, low blood volume and low blood pressure), ADH then targets the DCT
and collecting duct such that more water is reabsorbed from the urine into the
blood thereby increasing blood volume and pressure
= Aldosterone is released by the adrenal gland when low blood pressure is detected
by the kidney; when the kidney detects low blood pressure it releases renin which
converts inactive angiotensin into active angiotensin I and II; angiotensin II causes
the blood vessels of the kidney to constrict thereby raising the local blood
pressure; Angiotensin II also causes the adrenal glands to release aldosterone which
causes the kidneys to increase salt and water reabsorption from the urine into the
blood thereby increasing blood volume and pressure throughout the entire body
Page 17 of 17